London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

A student caught in a raging fire that killed 231 people in a Brazilian posted a message on Facebook pleading for help before she too fell victim.

Medical student Michele Cardoso, 20, had been at a party in Kiss club, Santa Maria with her sister Clarissa and boyfriend Joao Paulo.

They had been watching the band Gurizada Fandagueira when the muscians’ small pyrotechnics display set the roof on fire, causing poisonous smoke to fill the venue.

At 3.20am on Saturday, 50 minutes after the fire is reported to have started, Ms Cardoso posted a message on Facebook using her mobile phone which read: “Fire at KISS help”. Friends left increasingly desperate replies asking if she was alright, but her posts fell silent.

After she was confirmed dead, one friend wrote on her page: “I never imagined that it was serious when I first saw her asking for help on Facebook in the early hours, until I woke up with a message from my mum telling me what had happened.”

One of the club’s co-owners, Elissandro Spohr, has been detained by police. An arrest warrant has been issued for the other co-owner of the club in Santa Maria, Mauro Hoffman. The band’s lead singer, Marcelo Santos, was arrested as he attended the wake of bandmate Danilo Jacques, who died in the fire. The group’s security man was also detained.

Santa Maria is a university town in southern Brazil. Kiss was packed with up to 500 people, many of them students. At least 117 people are being treated in hospital. It has emerged that the venue’s fire safety licence had expired. It was also alleged that fire extinguishers did not work, and doormen stopped revellers from fleeing.

In Brazil most clubs issue customers with cards that they use to order drinks, paying at the door on the way out. It was claimed that doormen failed to realise the building was on fire and would only allow those who had paid their bill to leave.

Last night President Dilma Rousseff arrived at the scene after cutting cut short a visit to Chile, where she was taking part in a summit between the EU and Latin American nations. She wept as she comforted victims’ families, saying: “It’s a tragedy for all of us.”

A 30-day period of mourning was announced in Rio Grande do Sul state. As officials began naming the dead, it emerged that some of the clubbers were as young as 16 and had gained entry by using fake identification.

The fire started shortly after 2.30am as Gurizada Fandagueira opened their set. A flare thrown from the stage appears to have ignited soundproofing foam on the ceiling. Police said the blaze spread “in seconds”. Witnesses told of chaos as hundreds of clubbers scrambled for the exit through thick black smoke. Most victims died from inhaling toxic fumes or from being crushed in the panic, according to the fire service. Many clubbers confused the signs for the lavatory with exit signs and 50 people were found dead in the lavatories.

Footage recorded outside the club showed the desperate efforts of firemen and revellers to break open windows and punch holes in the club’s walls to free those trapped inside.

Detective Meinerz Sandro, who is leading the investigation into the fire, told reporters that one of the nightclub’s three owners has disappeared, while another has been questioned by officers.

In a statement, the nightclub said that all security staff were provided by a third party. Murilo de Toledo Tiecher, a 26-year-old medical student, told local media: “People were screaming ‘There’s a fire’ but the security guards didn’t budge and tried to keep the door shut.

“Five or six people knocked over one security guard and knocked down the door. It was the only exit.”

Revealing that the venue did not have a current fire safety licence, Lieutenant Colonel Moisés Silva Fuchs of the Santa Maria fire service said: “This licence expired in August and was not renewed.”